Digital guide
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Detailed content
- Output Ranges: 4-20 mA live zero or 0-20 mA (jumper-selectable); 0-10 V (jumper-selectable)
- Settling Time: 50 µs to ¼ LSB typical
- Isolation: 1500 V, surge-hardened with TVS diodes and opto-isolators
- Calibration: 8 front-access trim pots for offset and gain; 9 test points
- Indicators: 4 red + 1 amber LED channel health indicators
- Memory: 20+ EPROM/EEPROM devices
- Oscillator: Crystal oscillator for timing reference
- Form Factor: 6BA06
- Operating Temperature: -20°C to +70°C
- Qualification: IEEE 344 seismic qualified
Core Function
Converts digital speed, temperature, and load-demand words from the Mark IV CPU into precision analog voltages/currents that drive servo valves, IGV actuators, and remote indicators.
Typical Applications
- Gas turbine fuel and IGV control: drives ±10 V inputs to Woodward servo amplifiers for fuel-metering valves and IGV hydraulic actuators in Frame 7/9 units; 12-bit resolution achieves 0.025% fuel-flow accuracy
- Steam turbine governor and extraction control: 4-20 mA outputs drive Moog servo valves on governor and extraction pressure loops
- Remote indication and DCS interface: 0-10 V scaled signals feed plant DCS for remote load meters, temperature indicators, and vibration displays
Structural & Installation Notes
- Occupies a 6BA06 slot in the Mark IV rack via VME backplane
- Hardware-configured (no firmware download), deterministic operation
- Compatible with Mark IV TMR redundant architecture with online hot-swap support
- Surge suppression protects against >500 V spikes from lightning, VFD switching, or exciter flash-over
